1. Field of the Invention
The present technique relates generally to monitoring a physiological parameter of a patient. Specifically, the present technique is directed to the use of microneedles in physiological monitoring and drug delivery.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In the field of medicine, caregivers, such as doctors and nurses, desire to discover ailments in a timely manner in order to better care for patients. The passage of time prior to discovering an ailment may limit treatment options and, in some instances, may lead to irreversible damage. If an ailment is discovered early enough, however, a variety of remedial options and corrective actions may be initiated in order to treat the condition and prevent further damage to the health of the patient. Accordingly, healthcare professionals are continuously pursuing methods to expedite the diagnosis of a problem or to anticipate a potential problem in order to better serve their patients.
For example, a severe localized infection in a patient may lead to sepsis, or a generalized infection of the blood. Examples of such infections include urinary tract infections, infections of the liver or gall bladder, peritonitis, cellulitis, and bacterial pneumonia, among others. As the prognosis may be poor, an early determination that sepsis has set in is crucial for a positive outcome.
An early symptom of the development of sepsis is a decrease in microvascularization, or blood flow through the capillaries. While large vessels may be continuously perfused, smaller vessels decrease in density during sepsis. Currently, techniques to monitor bulk perfusion of a patient exist, such as pulse oximetry, but there is no objective, reliable, and accurate method for assessing the disruption of microvascularization.
Once sepsis has been diagnosed, early treatment may determine whether a favorable outcome is reached. As this treatment may involve large doses of broad spectrum antibiotics and compounds intended to increase blood flow to the capillaries, it is important to determine that sepsis is present before starting treatment to avoid unnecessary drug administration. The technique used to deliver the medicine may also be affected by the patient's condition.
Currently, three primary methods are used to deliver pharmacologically active substances into a patient: oral ingestion, injection, and transdermal absorption. While other methods exist, such as nasal sprays, inhalation systems, and through skin air-driven injections, most may be thought of as variations of the methods above. All three methods have limitations that make their use dependent on the patient's condition and the drug selected. For example, the decrease in microvascular circulation caused by some conditions, such as sepsis, may limit transdermal absorption. Further, persons in sepsis may not be able to consume drugs for treatment.
Furthermore, for conditions such as sepsis it may be desirable to measure a physiological characteristic of a patient (such as the microvascular response) or a chemical concentration of a compound in a patient in conjunction with drug delivery. Drug delivery approaches, such those described above, are typically not easily integrated with current monitoring techniques.
Accordingly, there would be significant value in a system that could be used to monitor localized physiological parameters. Such a technique would be especially useful in conjunction with the administration of pharmacologic substances.